Cowl



June 7, 1932.'

E. EMISCH C OWL Filed May 5. 193

Patented y June 7, 1932 EMIL `llilllISCI-, VOIE MAGDEBURG, GERMANY coWL Application iiied May 5, 1930, serial Nn.

Chimneys have sometimes such an unfavorable position that even with cowls there is no proper draught when a certain direction of windA is prevalent. Y

It has been proposedto obviate this inconvenience by enclosing the mouth of the smoke discharge pipe, circularin the upper portion, with an envelope which forms an annular space between itself and the smoke discharge pipe. The object is, to make the wind blow into this annular space, to suck the smoke out of the chimney and to conduct the same into the atmosphere. Owing to the cylindrical shape of the smoke discharge pipe almost the totality of the wind blowing against the same does not flow, into the annular space but divides and passes around the envelope. The small portion of the wind which enters the annular space remains ineffective, as it is lost in the annular space of comparatively large cross section and consequently reducing the velocity of thewind, so that this portion of the Wind can possess only little suction power which is further reduced by eddies formed when the stream lines of the wind join, which enters the annular space and moves around the end of the smoke discharge pipe.

It has further been proposed to join to the end of a substantially cylindrical smoke discharge pipe several wind channels open at the lower end, into which however no wind can enter as the wind blowing against the smoke discharge pipe will flow around the same to either side. These wind channels are therefore quite useless.

These inconveniences are obvated by the cowl according to the invention. In this cowl the smoke discharge pipe merges into a cap similar to a gabled roof directly exposed to the wind, on which a tube ending in the cap is mounted. This tube is roofed by a rotatable wind hood with a vane. From the tube wind channels are partitioned off adj acent the two inclined surfaces of the cap and of a cross section which is small in comparison with the cross section of the tube.

These wind channels open at the lower end v towards the inclined surfaces of the cap so 449,986, and in Germany J'une 26, 1929.

that they communicate with the outer air but 'A not withthe inner space of the cap. f Y The cowl is adjusted so that an inclinedv surface of the cap is standing opposite the unfavorable wind direction. The wind there- 5 5 fore blows against this inclined face, is deflected in upward direction and flows partly into the `wind channel adjacent to this in` clined face. As the crosssection of the chanv `nel is small, tliewind preserves its velocity e0 and exerts consequently a great suction force, which can be further increased if the wind channel is taperedin upward direction and if they inlet opening of the channel is'fitted with a wide paper-bag like extension capable to catchthe greatest possible quantity of wind. The smoke is drawn out of the chimney in that the rotatable wind hood conducts over thesmoke discharge tube` theV wind Whistling through the channel, s o that the 70 injector effect takes place. `An increase, also comparatively little, of the suction eect is possible, if the edge of the wind-` hood upwardly inclined with regard to the chimney axis is folded over gard to the vane. v

When `the windblows from .the opposite direction, thel other wind channel enters into operation, and when it blows from any of the two other directions, therwell known Vene- 78o tian blinds in the two gable walls .cause a suctioneffeet. TheseVenetian blinds can be made nozzle shaped to improve their effect, in order that the velocity of the wind be increased. S5

The cowl according to the invention increases the draft in the chimney not only when the wind is blowing from the unfavorable direction, but at all wind directions. The construction of the cowl is as simple as possible and verypractical. p' Y An embodiment of the invention is illustrated by way of example in the vaccompanying drawing in which Fig. l is a longitudinal section through the; 95 cowl on line l-lof Fig. 2.

Fig. 2 is a cross section on line 2 2 of Fi F ig. 3 is a longitudinal section on line 3 3 of Fig. 2, the wind hood being removed. ,100

perpendicularly with re- Y Fig. 4 shows an elevation corresponding tothe longitudinal section in Fig. 3.

Fig. 5 is a rear elevation of the wind hood. A tube 2 of square cross section is placed 5 on the chimney 1 and carries a cap 3 like a gable-roof open at the lower end. This cap 3 merges into a tube 4 which. carries a rotatablewind hood 5. Wind channels 7, com'- municating at the lower end with the atmospheric air, are separated by .vertical partitions 6 from the tube 4L which communicates with the interior of the cap 3, the cross sec- Y tion of said channels being small compared f with the remaining cross section of thetube. These channels end close over the two inclined surfaces Siof the cap 3 which shut 0E the channels from the inner space of the cap'. `Each channel 7 has at the lower end an entrance opening 9 for the air.V y Y The two gable sides of cap consist of Venetian blinds 10 which, as shown on the, right side in Fig. 3, may form gaps 11 narrowing nozzle like,.to increase the velocity. of the onblowing wind. The nozzle shape of the gaps might be obtained by increasing the angle of inclination of the Venetian blinds 10 from, abovedownward. The Venetian blinds might be made longer.

VThe edge 12 of the wind hood is bent at right angles, as best shown in Fig. 5, so that i it oiiers to thewind a surface for action. The hood 5 carrying avane 13 is composed of f three parts. The several parts form, in known manner, nozzle like air 'inlet slots 14. The

sides of the square tube with Venetian blinds.

I claim A cowl, comprising in combination with the smoke discharge pipe, a gable-roofshaped cap on the yupper end of said pipe, end walls on said cap having gaps communicating directly with the atmosphere adapted to guide the wind into the interior of said cap, a cylindrical tube on and forming an extension of said cap; lateral wind channels of comparatively small cross-'section extendingthe entire length of and'partitioned off from the interior of said cylindrical tube, and a'rotatable hood on. and covering the upper end of said tube composed of a plurality of overlappingfpart's inclined vrelative to the chimney axis and arranged with intervening gaps adapted to allow the passage of air,the upper edge of the upperpart of said hood being bent upwards, and a vane Von the upper sideo theupper part of said hood for steer ing said hood. -f

Intestimony whereof I affin signature.

'EMIL EMISCIL hood rotates aro-und a bolt 15 mounted in a Y bridge 1.6. y

Y In Fig. 1 the courses of flow of the wind and of the smoke are indicated by lines with arrow heads. 40 by a single arrow head and the smoke lines by double arrow heads. The suction force or" the windblowing against the inclined face 8 and through the channel 7 is further increased by the wind enteringv into the wind hood and by the wind getting under the cap 3. The tube 2, in order to impart to the wind an upwardly'directed component, is enclosed for example by a concrete envelope 17. Av further increasing of the suction force is ef- The wind lines are indicated y ,fected by the outwardly bent upper edge 15 of the wind hood, whichV imparts tothe rWind a sudden change of' direction thereby forming a vacuum. v

When the Wind blows against the gable sides of the cap, it flows, instead through one of the channels 7, through the gaps formed by the Venetian blinds 10.

Under certain conditions it is advisable, f to arrange above the wind channels deflec'tors 30 designed to conduct the air from the channels over the smoke discharge pipe. If the cap 3 is closed at the lower end, the

concrete envelope 17 is not necessary. In v order to Vobtain even then an increase of the v suction ei'ecgit is advisable to it all the jeo 

